The field of Cultural Heritage has inspired, in the course of last few years, an interest more and more important on behalf of scientific community that deals to survey. The idea that knowledge of a site doesn't apply only to its history but must necessarily include its characteristics of position, shape and geometry, is gathering pace. In Geomatic science the field of cultural heritage benefits to an integrated approach of techniques and different technologies. Every cultural site in fact, is a case in itself, with its own characteristics, problems and specificness. Current techniques offer opportunity to achieve new ways of representation and visualization of cultural site, with the aim of a better metric description. This techniques are powerful tools for analysis of sites and supports to activity of reconstruction and repair. Biggest expectations in this field is laser three-dimensional scanning technique; a system which is able to operate in a methodical way in speed of acquisition and in possibility to access data in real time. Documentation and filing of state of a monument or site is essential in case of reconstruction or conservative project. Possibility to detect very complex geometries with great accuracy allows an in depth study of constructive techniques, making analysis of geometrical details easier which is, with traditional techniques, difficult to achieve. Biggest problems about use of laser scanner survey are graphic outputs for restorers and architects, in fact they often don't know real potential of this techniques, methodologies and functionalities and they expect traditional outputs such as floor plans, cross sections and front elevation of cultural asset. Present study is focused on finding a workflow to support activity of study, restoration and conservative project of cultural heritage, extracting automatically (or with a limited manual operation) graphic outputs from laser scanner survey. Some procedure was tested on two case study the Siviller Castle (XV century), situated in Villasor, a city near Cagliari (Sardinia, Italy) and the tower bell of Mores, near Sassari (Sardinia, Italy). The cultural sites were surveyed with laser scanner Focus 3D by Faro and to process clouds point we were used the JRC 3D Reconstructor software * Corresponding author. This is useful to know for communication with the appropriate person in cases with more than one author.

In order to monitor the coastal-sea environment it is necessary to check variations of the coastal line as well as the sea bottom. There are techniques for using remote sensing as a technique for the extraction of bathymetric information. However, these techniques require preliminary radiometric image processing in order to fulfill the model constraints. More precisely, atmospheric effects must be removed together with the water column correction in order to achieve radiometric values that are only representative of the sea depth and to homogenize the upwelling response from different bottom types. If sun-glint is present, the effect of the sun beams reflecting on the sea surface, it has to be corrected by a special procedure. This work is concerned with pre-processing the images, via the development of a module in IDL (Interactive Data Language). This module was subsequently embedded in the ENVI menu system. The model was applied to Ikonos and WorldView-2 scenes, representing respectively the Poetto beach near the city of Cagliari and the littoral of Marina di Altidona (the Marches, Italy). The results of pre-processing were evaluated using an unsupervised classification

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ABSTRACT:The fundamental principle underlying the methods used to extract bathymetric information from remote-sensed imagery is that different wavelengths of the solar light penetrate the water body to different depths. In order to extract bathymetric values from multispectral satellite imagery we implemented the Jupp method (Jupp, 1988), in IDL language and integrated it in the ENVI menu structure. In this experiment we apply this method to two images of the Poetto beach in Cagliari (Sardinia, Italy) acquired from the new-generation WorldView-2 sensor. Launched in October 2009, the WorldView-2 sensor provides, among others, one (named Coastal) that was designed specifically for this kind of analysis; we chose to use the Coastal band in place of the Blue one when applying the model. The images (a stereoscopic pair) were acquired on June 17, 2011. The 5419 scene was pre-processed in order to separate the sea bottom classes. This class was then georeferenced to overlap on the 5318 scene. A traditional bathymetric survey was performed, up to 1,50 m, planned and carried out in order to calibrate the model. For each scene, 10 calibration areas were selected, and for each of them a digital model of the sea bottom was generated. Precision and accuracy of the method were evaluated by analyzing the results extracted from the stereo-pairs and by examining the correlation between the surveyed depth values and the calculated ones, between the different models calculated from the same scene using different calibration areas, and between the models obtained from the two images.

ABSTRACT:The use of GIS as a tool for archival, analysis and representation of geographic information has become significantly popular in many scientific fields that are directly concerned with the "territory" as their object of study. The field of application of GIS, however, has expanded also in other areas, such as those related to humanities and architecture, in which the territory is studied in an "indirect" mode because it constitutes a kind of substrate on which to develop a specific spatial analysis for particular purposes. Among these areas are to be included certainly archeology and restoration, fields in which the GIS has become a useful tool for historical studies. In this work we present a GIS developed for the study of the historical and territorial coastal defense system of Sardinia (16 th -18 th century), in order to respond to the need to store, analyze and efficiently manage the information regarding cultural heritage and landscape heritage such as that consisting of the coastal defensive towers of Sardinia. This defensive system, in fact, was composed by over 100 towers positioned around the entire coastal perimeter of Sardinia, of which more than 90 still exist today. Their position was planned on the basis of the following criteria: -Warning the neighboring towers about the sighting of enemy ships -Protecting coasts located near the towns -Monitoring the water sources near the coast -Allowing for the full visibility of the coasts of any morphology With this study we also verified, through the use of high resolution and high accuracy DTM (LiDAR) and the topographic databases, whether the positioning criteria specified in the design of the system were respected and effective.

Cagliari, county seat of Sardinia Region (Italy), situated in the southern part of the island, is characterized by a subsoil full of cavities. The excavations in fact, which lasted more than 4000 years, had a great development due also to the special geological characteristics of the city subsoil. The underground voids, which the city is rich in, belong to different classes such as hydraulic structures (aqueducts, cisterns, wells, etc.), settlement works (tunnels, bomb shelters, tombs etc.) and various works (quarries, natural caves, etc.). This paper describes the phases of the survey of a large cavity below a high-traffic square near the Faculty of Engineering in the city of Cagliari, where the research team works.. The cave, which is part of a larger complex, is important because it was used in the thirteenth century (known as the Pisan age) as a stone quarry. There are traces of this activity that have to be protected. Moreover, during the last forty years the continuous crossover of vehicles cracked the roof of the cave compromising the stability of the entire area. Consequently a plan was developed to make the whole cavity safe and usable for visits. The study of the safety of the cave has involved different professionals among which geologists, engineers, constructors. The goal of the University of Cagliari geomatic team was to solve two problems: to obtain geometrical information about the void and correctly place the cave in the context of existing maps. The survey and the products, useful for the investigation of the technicians involved, had to comply with tolerances of 3 cm in the horizontal and 5 cm in the vertical component. The approach chosen for this purpose was to integrate different geomatic techniques. The cave was surveyed using a laser scanner (Faro Photon 80) in order to obtain a 3D model of the cave from which all the geometrical information was derived, while both classic topography and GPS techniques were used to include the cave in the city map.

Commission VII, WG VII/5 KEY WORDS: Bathymetry, Remote Sensing, Coastal Erosion, IDL ABSTRACT:There is an ongoing effort in using imagery from remote sensing platforms to obtain information about the sea depth; this allows to monitor the dynamics of coastal erosion without the need for costly and repeated local surveys. We worked on a new implementation of the Jupp method to extract depth information from satellite images. Our software is based on previous implementations of the algorithm in the IDL language, but we made our current implementation more modular in order to make possible experimentations with different approaches. We used this implementation on a series of six images (three from the Landsat TM sensor and three from the Landsat OLI sensor) in order to improve the available tools. We established an iterative workflow for working on the Landat-8 images widely exposed in this paper.

Abstract. The surveying and management of telecommunication towers poses a series of engineering challenges. Not only they must be regularly inspected for the purpose of checking for issues that require maintenance interventions, but they are often sub-let by their owners to communication companies, requiring a survey of the many (several thousand per company) installed appliances to check that they respect the established contracts. This requires a surveying methodology that is fast and possibly automated. Photogrammetric techniques using UAV-mounted cameras seem to offer a solution that is both suitable and economical. Our research team was asked to evaluate whether, from the information acquired by small drones it was possible to obtain geometric information on the structure, with what degree of accuracy and what level of detail. The workflow of this process is naturally articulated in three steps: the acquisition, the construction of the point cloud, and the extraction of geometries. The case study is a tower carrying antennas owned by several operators and placed in the industrial district of Cagliari. The article examines the problems found in modelling such structures using point clouds derived from the Structure-from-Motion technique, in order to obtain a model of nodes and beams suitable for the reconstruction of the structure’s geometric elements, and possibly for a finite elements analysis or for populating GIS and BIM, either automatically or with minimal user intervention. In order to achieve this, we have used voxelization and skeleton extraction algorithms to obtain a 3D graph of the structure. The analysis of the results was carried out by varying the parameters relating to the voxel size, which defines the resolution, and the density of the points contained inside each voxel.